-LRB- CNN -RRB- -- The holiday season is always a win for video gamers , as software makers jockey to one-up each other with slicker graphics , deeper play and more expansive 3-D worlds .

But the larger and more complex modern-day epics like `` Fable III '' and `` Fallout : New Vegas '' become , the more it often pays to keep things simple .

Classics such as `` Tetris '' and `` Pac-Man '' clearly illustrate this principle . As engaging today as they were when first launched decades back , it 's these titles ' sheer approachability and user-friendliness that make them timeless .

Even the most sprawling modern-day gaming experiences , such as `` World of Warcraft '' and `` Call of Duty : Black Ops , '' still bow to the classic game design principle of keeping play easy to learn but hard to master .

The successful games observe two vital rules :

1 -RRB- Find clever ways to spin the same basic concept -LRB- swapping tiles , stomping enemy heads , etc. -RRB- multiple times

2 -RRB- Tip learning curves in the players ' favor by slowly introducing added depth at a comfortable pace

There 's a reason why social games , including `` FarmVille '' and `` Mafia Wars , '' and iPhone apps such as `` Angry Birds '' and `` Pocket God '' continue to rack up millions of plays .

It 's not that these titles are revolutionary in design . It 's that although the games are easy to start playing and enjoying , they increase in depth and complexity as the player gains more skill .

This makes it less intimidating for players of all levels to try these games , which slowly entice us into their web . -LRB- Admittedly , the games ' low price points , on-demand access and ample personality do n't hurt either . -RRB-

Make no mistake : Hardcore gaming enthusiasts do demand more value and substance from their titles than casual gamers . So designers are creating more robust virtual realms and expanding titles ' value and scope through downloadable updates .

Games in role-playing , simulation and strategy genres also thrive by adding greater intricacy , not less . In short , we 'd weep for a world without the latest `` Civilization '' or `` Gran Turismo . ''

Instead of piling on pointless game variants or needlessly complicated controls , the most popular mass-appeal games often focus on executing a few simple features well -- and presenting them in endlessly novel contexts . What is `` Torchlight '' if not a smartly-placed series of mouse clicks , `` Bejeweled '' a simple slider puzzle or `` Guitar Hero : Warriors of Rock '' a more high-tech version of Simon ?

No player likes to feel as if their favorite titles have been dumbed down . No designer appreciates admitting that behind all the fancy mission types , play modes and monsters , their basic play concept amounts to `` checkers with a twist , '' or simply tapping the right keys on cue .

Still , why overcomplicate matters ? Freeform missions , jaw-dropping graphics and extensive online multiplayer support make excellent window dressing . But even in the era of sprawling odysseys like `` Alan Wake '' and `` Red Dead Redemption , '' they remain secondary to a fun , engaging and approachable core game experience .

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Simple games , including such classics as `` Tetris , '' are less intimidating to newcomers

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The most popular games often focus on executing a few simple features well

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Hardcore gamers still love complex challenges , and no one likes to feel their favorite titles have been dumbed down